[omnisharp-plugin] Markdowns are not displayed in the editor

[svor]

Describe the bug

Markdowns are not displayed in the editor for C# files. And if move the cursor to the place where an icon should be I see next error in the browser console:

Exception

Uncaught Error: Cannot read property 'language' of null
TypeError: Cannot read property 'language' of null
    at e.asMarkdownString (vendors.795ac5958e7158cc3edd.js:1)
    at vendors.795ac5958e7158cc3edd.js:1
    at Array.map (<anonymous>)
    at e.asHoverContent (vendors.795ac5958e7158cc3edd.js:1)
    at e.asHover (vendors.795ac5958e7158cc3edd.js:1)
    at vendors.795ac5958e7158cc3edd.js:19
    at async Promise.all (/dashboard/index 0)
    at errors.ts:81

omnisharp plug-in, which provides the functionality of omnisharp language server is here https://github.com/redhat-developer/omnisharp-theia-plugin

Che version

• latest
• nightly
• other: please specify

Steps to reproduce

You can follow steps in the video: https://youtu.be/Zkm513MgBl8

[rhopp]

Triaging the issue the same as it's parent issue. If you think this issue should be triaged for Che 7 GA, speak up ;-)

[slemeur]

@svor Can you precise what markdowns cannot be displayed and where ?
The issue is a bit obscur to me :)

[svor]

@slemeur for example QuickFixe icons:

[svor]

should be fixed by eclipse-che/che-plugin-registry#199

[svor]

fixed by eclipse-che/che-plugin-registry#199